【读书2】【2014】基于MATLAB的雷达信号处理基础（第二版）——雷达时标(1)

应用于单个脉冲数据的操作发生在最短的时间尺度上，通常称为快时间，因为在某些情况下，由瞬时脉冲带宽(参见第2章)确定的采样速率在几百千赫(kHz)到几千兆赫的量级。

Operations that are applied to data from asingle pulse occur on the shortest time scale, often referred to as fast timebecause the sample rate, determined by the instantaneous pulse bandwidth (seeChap. 2), is on the order of hundreds of kilohertz (kHz) to as much as a fewgigahertz in some cases.

相应的采样间隔从几微秒到几分之一纳秒，因此对这些样本的信号处理倾向于在类似的时间间隔上操作。

Corresponding sampling intervals range froma few microseconds down to a fraction of a nanosecond, and signal processingoperations on these samples therefore tend to act over similar time intervals.

典型的快时间操作是数字I/Q信号形成、波束形成、脉冲压缩或匹配滤波以及灵敏度时间控制。

Typical fast time operations are digitalI/Q signal formation, beamforming, pulse compression or matched filtering, andsensitivity time control.

信号处理的下一级是对来自多个脉冲的数据进行操作。

The next level up in signal processingoperations operates on data from multiple pulses.

脉冲之间的采样间隔(PRI)通常为几十微秒到几百毫秒的量级，因此涉及多个脉冲的操作都占用类似的时间尺度。

The sampling interval between pulses (thePRI) is typically on the order of tens of microseconds to hundreds ofmilliseconds, so again operations that involve multiple pulses occupy similartime scales.

由于与单脉冲操作相比，脉冲之间的采样速率要慢得多，所以这种操作被称为在慢时间起作用。

Due to the much slower sampling rate comparedto single-pulse operations, such operations are said to act in slow time.

典型的操作包括相干和非相干积累、所有类型的多普勒处理、合成孔径成像和空时自适应处理。

Typical operations include coherent andnoncoherent integration, Doppler processing of all types, synthetic apertureimaging, and space-time adaptive processing.

在第三章中讨论数据立方体的概念时，将重新讨论慢时间和快时间。

The idea of slow and fast time will berevisited in the discussion of the data organizational concept of the datacubein Chap. 3.

例如通过多普勒处理或合成孔径雷达(SAR)成像以某种方式相干组合而成的一组脉冲，就称为相干处理间隔(CPI)。

A group of pulses that are to be somehowcombined coherently, for example via Doppler processing or synthetic apertureradar (SAR) imaging, are said to form a coherent processing interval (CPI).

更高级的雷达处理对来自多个CPI的数据进行操作，因此在更长的时间尺度上操作，通常称为驻留，典型持续时间一般为毫秒量级到1或几十秒量级。

A still higher level of radar processingacts on data from multiple CPIs and therefore operates on an even longer timescale often called a dwell and typically lasting milliseconds to ones or tensof seconds.

这种尺度的操作包括多CPI检测、模糊度分辨技术、多视SAR成像和跟踪滤波。

Operations on this scale includemultiple-CPI detection and ambiguity resolution techniques, multilook SARimaging, and track filtering.

一些雷达可以使用来自多个驻留点的数据跟踪被检测目标，并持续好多秒或好几分钟。

Some radars may track detected targets formany seconds or minutes using data from multiple dwells.

跟踪滤波器就在这种情况下工作。

Track filtering operates in this regime.

最后，一些成像雷达可以在数天、数月甚至数年内监测同一个区域。

Finally, some imaging radars may monitor anarea over days, months, or even years.

1.5.2. 本质现象

1.5.2. Phenomenology

为了设计一个成功的信号处理器，必须理解要处理的信号的本质特性。

To design a successful signal processor,the nature of the signals to be processed must be understood.

本质现象是指雷达接收信号的特性。

Phenomenology refers to the characteristicsof the signals received by the radar.

相关的特性包括信号功率、频率、相位、极化或到达角；时间和空间位置的变化；以及随机性。

Relevant characteristics include signalpower, frequency, phase, polarization, or angle of arrival; variation in timeand spatial location; and randomness.

接收信号的本质现象是由引起雷达回波的物体的本质特征决定的，例如它们的物理尺寸或相对于雷达的方向和速度、以及雷达本身的特性，例如雷达发射波形、极化或天线增益。

The received signal phenomenology isdetermined by both intrinsic features of the physical object(s) giving rise tothe radar echo, such as their physical size or their orientation and velocityrelative to the radar; and the characteristics of the radar itself such as itstransmitted waveform, polarization, or antenna gain.

——本文译自Mark A. Richards所著的《Fundamentals of Radar Signal Processing（Second edition）》

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